Unit 3 Review Questions Flashcards
What are diuretics?
Compounds that cause fluid loss through increased urine volume.
-caffiene due to vasdialation in nephron
-alcohol due to ADH inhibition
high glucose levels
lasix which decrease the medullary osmotic gradient or prevent it’s formation
Discuss the anatomy of the oral cavity. What type of digestion occurs here?
NKSSE
contains teeth and tongue
mostly mechanical digestion, small amount of chemical digestion
How does gastric filling, mixing, and emptying occur?
Filling: reflexive relaxation coordinated by swallowing center of the brain stem. Stress-relaxation response of smooth muscle
Peristaltic waves: mix food with gastric juice to create chyme. More powerful near pylorus
Emptying: peristaltic waves force 3ml of chime through pyloric sphnicter. Empties in 2-4 hours. Carb rich exits first, lipid rich leaves last
What structures make the renal corpuscle?
glomerulus and bowman’s capsule (parietal layer and visceral layer (podocytes)
Discuss the structures of the filtration membrane and how they are specialized for their function.
fenestrated simple squamous epithelium of glomeruler capillary
shared basement membrane
slit membrane between pedicels of podocytes
very permeable to allow filtrate out of blood
Carbohydrate Digestion
Starch and disaccharides ingested
oral cavity: Salivary amylase digests carbs down to oligosaccharides, dextrin, and disaccharides
small intestine:
-pancreatic amylase breaks them down to smaller oligosaccharides and disaccharides (lactose, sucrose, and maltose)
-Brush border enzymes alpha-dextrinase, lactase, sucrase, and maltase break them down into glucose, fructose, and galactose (monosaccharides)
-Absorbed by enterocytes and brought back to the liver through the hepatic portal vein
Describe the structure and function of the pharynx
Pharynx-functions in swallowing(deglutition). Voluntary oral phase, pharyngeal phase and esophageal phase controlled by medulla
- Discuss the 3 stages of gastric regulation.
- cephalic phase
-stimulatory events: smell, thought, taste, sigh of food
-medulla+hypothalamus->vagus nerve->increased secretions
-inhibited by illness, SNS, or disgust - Gastric phase
-stimulatory events: distension of the stomach from bolus, proteins in food, alkaline environment, or caffeine
-enteroendocrine cells secrete gastrin to increase gastric juice
-inhibited by SNS - Intestinal phase
-brief stimulatory event: enteroendocrine cells in the duodenum secrete intestinal gastrin to increase gastric juice
-inhibitory event: duodenum enteroendocrine cells secrete cholecystokinin and scretin when duodenum is full to decrease gastic juices.
Protein digestion
Stomach: pepsin breaks them down into large polypeptides
small intestine:
-Pancreatic enzymes trypsin, chymotrypsin, and carboxypeptidase break them down into small polypeptides and dipeptides
-Brush border enzymes carboxypeptidase, aminopeptidase, and dipeptidase break them down into amino acids
-Absorbed by enterocytes and takes to liver via hepatic portal vein
Submucosa
loose areolar connective tissue with blood and lymph vessels, elastic fibers, nerves, glands, and malt. submucosal nerve plexus.
Discuss the importance of bacterial flora.
Ferment indigestible carbs and mucus
release gases that create flatus
synthesize vitamin K
keep pathogenic bacteria in check
may influence weight, mood, and susceptibility to some diseases like diabetes
What is the countercurrent exchanger and where is it located
The vasa recta, preserves the osmotic gradient in the renal medulla
What enzymes are secreted by the pancreas?
Protein:
trypsinogen->trypsin (converted by brush border enzyme enteropeptidase
chymotrypsinogen->chymotrypsin
procarboxypeptidase->carboxypeptidase
Pancreatic amylase (carbs)
pancreatic lipase (fats)
ribonuclease and deoxyribonuclease (RNA and DNA)
What is saliva and how is salivation controlled?
-secrete slightly acidic saliva that contains water, ions, salivary amylase, proteins, mucin, lysozyme, metabolic wastes, and IgA.
-minor glands keep mouth moist
-stimuli such as taste chemoreceptors, mechanoreceptors, sight/smell/thought of food, or irritated GI tract send impulses to salivary nuclei in pons->parasympathetic impulses to salivary glands to secrete saliva
Nucleic acid digestion
Small intestine:
-pancreatic enzymes ribonuclease and deoxyribonuclease digest them down to nucleotides
-brush border enzymes digest them down to phosphate group, pentose sugar, and nitrogenous base
-returned to liver via hepatic portal vein
Serosa or adventitia
Serosa in abdominal cavity, peritoneum
adventitia outside of abdominal cavity (collagen fibers)
Describe the function of cholecystokinin
CCK: secreted in response to fats and proteins in chyme
-targets:
pancreatic acinar cells to increase enzyme production
gall bladder to contract
hepatopancreatic sphincter to open and release
stomach to decrease gastric juices
tells hypothalamus we are full
Urine formation: secretion
-occurs throughout renal tubule and collecting duct
-important for adding substances to urine, disposing of urea/uric acid/ammonia, controlling blood pH, getting rid of excess K+ from Na+/K+ pump
What is the function of hepatocytes?
processes and filters nutrient-rich blood, create bile
Discuss the structure and function of the peritoneum. What are mesenteries and where are they found?
Protection, anchoring, and reduction of friction.
Double serous membrane
found in the abdominal cavity
What are the important structural modifications in the small intestine (think about surface area)?
circular folds, microvilli, and villi
Where are nephrons found within the kidney?
In the cortex and the medulla
What are the accessory organs in the digestive system?
Tongue, teeth, salivary glands, gall bladder, and pancreas
Discuss the different cell types (4) found in the mucosa and the importance of their secretions. How do these secretions work together? What protects the stomach lining from these secretions?
-mucus neck cells: thins acid mucous
-parietal cells- secrete HCl and intrinsic factor (needed for B12 absorption). HCl denatures proteins and activates pepsinogen
-Chief cells: secrete pepsinogen and gastric lipase. Pepsinogen becomes pepsin which is an active protease. Gastric lipase digests milk fats
-Enteroendocrine G cell: secretes gastrin into blood which makes parietal cells secrete more gastric juice
Stomach lining protected by mucus.
distal convoluted tubule, substances are reabsorbed or secreted
-aldosterone causes Na+ absorption and K+ secretion (Na+/K+ pumps)
-parathyroid hormone causes increased calcium reabsorption
-atrial natriuretic peptide causes decreased H2O reabsorption
Discuss the flow of blood and bile through a lobule (and through the liver).
Bile: hepatocytes->bile canaliculi->bile duct->R+L hepatic duct-> common hepatic duct->common bile duct-> duodenum
Blood-> hepatic arteries and portal veins->sinusoids->central vein-> hepatic vein->inferior vena cava
describe salivary glands
minor salivary glands in mouth and tongue but major ones located outside oral cavity
-parotid, submandibular, and sublingual
-contain serous and mucous cells
Urine formation- filtration
Net filtration pressure: pressure responsible for filtration formation. 10mmHg
-glomerular blood hydrostatic pressure: 55 mmHg, pressure of blood against capillary walls
-capsular hydrostatic pressure: 15 mmHg, pressure of fluid in the capsular space pressing against capillary
-blood colloid osmotic pressure: 30mmHg, pressure of blood pulling back in capillary
Glomerular filtration rate: volume of filtration formed by both kidneys per minute
-controlled by renal blood flow
-too high , too low absorption
-too low, too high absorption
What are the functions of the stomach? What type of digestion occurs here?
mechanical and chemical digestion
very little absorption
What organs make up the alimentary canal?
Mouth, oro and laryngopharynx, esophagus, stomach, small intestine, large intestine, rectum, and anus.
Describe the functions of the kidneys
filter blood and remove nitrogen compound waste and drugs
regulate blood plasma makeup (pH, blood pressure, solute concentrations)
hormone production (erythropoietin and renin)
activate vitamin D (cholecalciferol to calcitrol)
absorb Ca2+ from diet
What is digested and what is absorbed in the small intestine?
All macromolecules digested, nutrients absorbed.
What is the difference between the two groups of organs?
One is the main digester, on assists in digesting